A secret ballot will also be held for the leader of the Nationals - the position that comes with that of deputy prime minister.

Spills are fast-moving events, and change as deals are done and promises are made.

As of today, Joyce had about 10 backers - one short of what was needed to claim victory.

Joyce is the dark horse. His fate could depend on how McKenzie - who looks like she is backing Joyce - and his former chief-of-staff, Matt Canavan, vote.

The Nationals have 21 parliamentarians, including eight in Queensland, eight in NSW, Victoria has four and Northern Territory has Sam McMahon.

Queenslanders George Christensen, O'Brien, Ken O'Dowd, Susan McDonald, David Littleproud - in contention for the deputy position - will likely vote for Joyce. Littleproud will be up against David Gillespie and possibly Keith Pitt.

McKenzie will likely bring McMahon with her.

Gillespie will also likely vote for Joyce, as is tipped Pat Conaghan.

With Joyce's own vote, he is one short, and possibly will get there.

O'Brien is a staunch Joyce supporter. He has supported Joyce through all the tough times, and believes the former deputy prime minister has done his time in political purgatory.

Joyce should no longer be punished as someone who had an affair, his supporters argue. It wasn't a fling with former staff member Vikki Campion. They are now a new family, raising two young children.

Many conservatives, mostly Nationals, love crazy, affable Barnaby.

Crazy, loopy Barnaby scares the bejesus out of them, and over the summer there were glimpses of what can be described as a rambling man shaking a stick at the sky.

He hit the airwaves today to show he is in control, that crazy affable Barnaby is back.

Joyce still has the X-factor. He can cut through political spin like a hot knife through butter.

He can raise money. He can pull a crowd and, most importantly for the Nationals, he refuses to let Liberals bully the junior party into submission.

Many believe McCormack has rolled on to his belly too many times, especially in Cabinet and the treasured Coalition Agreement.

And let's be clear. The numbers McCormack has are not because they think he is doing a stellar job, it's because they either do not like Joyce or will be rewarded for sticking with the incumbent.

The other issue is that McCormack's selling point is not strong. His record as leader is woeful and his colleagues know that Nationals did not hold their seats because of him, but because of Scott Morrison.

Joyce, unlike McCormack is also able to offer more treats - he can and will offer to get more for Nationals, a stronger Coalition Agreement and a greater, more forceful voice in Cabinet.

Darren Chester ruled himself of running for leader or deputy because McCormack has likely offered him a Cabinet position if McCormack remains leader. For Chester, that's enough.

If Joyce just falls short, McCormack's days will be numbered.

There is a lesson here for the Liberal Party. They were happy to have an anaemic Nationals leader because it was easier.

But having a weak Nationals leader causes instability, and a strong Nationals makes for a strong Coalition.